Emission control devices, such as diesel particulate filters (DPF), may reduce the amount of soot emissions from a diesel engine by trapping soot particles. Such devices may be regenerated during operation of the engine, to decrease the amount of trapped particulate matter. Regeneration is typically achieved by raising a temperature of the DPF to a predetermined level, maintaining the temperature at the predetermined level, and ensuring that exhaust gas entering the DPF is of a certain composition in order to burn or oxidize the particulate matter.
One approach for controlling filter regeneration includes initiating a regeneration event in response to an amount of particulate in the filter increasing above a threshold amount, and terminating the regeneration event in response to the amount of particulate decreasing below the threshold amount or in response to vehicle operating in conditions that are not favorable for regeneration such as during idle stop conditions.
However, the inventors herein have recognized issues with such an approach. For example, during vehicle operation when conditions for sustained full regeneration are seldom available, such as during urban driving conditions including frequent idle stops and light load operation, regenerating based on soot load may induce frequent premature regeneration terminations before the DPF is fully regenerated. The premature terminations result in increased regeneration frequency leading to increased regeneration fuel penalty (RFP), and reduced fuel economy.
In one example, the above issues may be at least partially addressed by a method, comprising: selectively regenerating a diesel particulate filter based on a soot load, a predicted destination distance, and an estimated ability to maintain a desired vehicle speed greater than a threshold speed for a threshold duration, the particulate filter receiving exhaust from an engine combusting diesel fuel, wherein the estimation is based on a current vehicle speed, and an average vehicle network speed of other vehicles within a vehicle to vehicle network. In this way, by utilizing information from the vehicle network, intelligent decisions related to DPF regeneration including initiation and termination of regeneration may be made for reduced RFP and improved fuel economy.
As an example, a control network (e.g., CAN) of a target vehicle including a DPF may be connected to a vehicle-to-vehicle network including a group of vehicles travelling ahead of the target vehicle and within a threshold distance. Further, the control network of the target vehicle may be connected to a vehicle navigation system linked to a global positioning system providing travel route information and location information. In response to a soot load greater than a threshold amount, opportunistic regeneration parameters including cost of regeneration, and cost of filling the DPF under current vehicle operating conditions may be determined. The cost of regeneration may be based on current vehicle operating conditions including the soot load, exhaust temperature, pressure difference across the DPF; and further based on information from the vehicle-to-vehicle network including an estimated ability to maintain a desired vehicle speed for a threshold duration. In response to the cost of regeneration decreasing below the cost of filling, DPF regeneration may be initiated, and in response to the cost of regeneration increasing above the cost of filling, DPF regeneration may be terminated. Further, a degree of regeneration (e.g., full regeneration, partial regeneration) may be determined based on the estimated ability.
In this way, when the soot load is within a regeneration range, information from the vehicle-to-vehicle network and the vehicle navigation system may be utilized to perform opportunistic regenerations so as to reduce the frequency of premature regeneration terminations, and to identify and improve efficiency of partial regeneration opportunities, and thereby, reduce regeneration fuel penalty and improve fuel economy.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.